eh?

hello, i have an xhtml complient website apart from one page and i don't know 
what the errors mean.....

  ... h="13"><a href="rate.php?value=neg&dnl=01"><img src="/image/neg ...
 Error: unknown entity "dnl" 

  ... h="13"><a href="rate.php?value=neg&dnl=01"><img src="/image/neg ...
 Error: reference not terminated by refc delimiter 

What is REFC......? how can i get rid of these errors so??
Please help!

<A HREF="www.talio.co.uk">www.talio.co.uk</A>